1. Field of the Invention. The subject invention relates to a connector assembly for a vial, and more particularly, to a multipositional resealable vial connector that enables an efficient transfer of liquid into or out of the vial.
2. Description of the Prior Art. Many drugs are presented in dry form to achieve a longer shelf life. One type of dry drug is a lyophilized drug. A selected dose of a lyophilized drug may be stored in a glass vial that is sealed to prevent deterioration or contamination of the drug. A liquid solvent may be mixed with the lyophilized drug shortly prior to use, and the drug solution may be administered to a patient.
Some prior art vials of lyophilized drugs are sealed with a membrane that can be pierced by a needle or spike for delivering the liquid solvent into the vial and for subsequently administering the drug solution to a patient. It has been found, however, that fragments of the membrane can separate when the seal is being pierced, and thus inadvertently can be administered to a patient with the drug solution.
Other prior art vials include a rubber stopper that is urged into the vial by the spike, needle or other tubular structure that delivers the solvent to the vial. These stoppers cannot be conveniently accessed after they have fallen into the vial for reliably resealing the vial of drug solution. However, the loose stopper can unintentionally block the vial opening to impede the outflow of drug solution.
A very effective vial connector assembly is shown in U.S. Pat. No. 5,358,501 which issued to Gabriel Meyer on Oct. 25, 1994. Certain embodiments of the assembly shown in U.S. Pat. No. 5,358,501 include a tube with a proximal end in the vial and a distal end externally of the vial. First and second channels extend axially through the tubes. The first channel terminates at a first orifice at the extreme proximal end of the tube. The second channel terminates at a second orifice disposed distally of the first orifice. Portions of the tube defining the first orifice prevent the stopper from blocking the second orifice. Hence a drug solution in the vial can be completely emptied for administration to a patient. Other embodiments shown in U.S. Pat. No. 5,358,501 attach the stopper to the tubular structure that urges the stopper into the vial. Thus, the stopper does not fall to the bottom of the vial. This enables the vial to be re-sealed and further prevents the stopper from inadvertently falling into a position where the stopper can impede the flow of drug solution from the vial.
In many situations it is desirable to utilize a pointed spike on the vial connector to access a supply of solvent in a rigid container. It has been found that surface tension at the gas/liquid interface and a pressure differential between the vial and the container of solvent prevents the initial flow of solvent into the vial. Similar problems with pressure differential and surface tension may occur when the drug solution is being delivered from the vial. Where the container is a flexible container, such as a flexible infusion bag, it may be possible to squeeze the infusion bag to initiate fluid flow. However, if the container is rigid, this approach is not possible. Some medical practitioners overcome this problem by shaking the vial after it has been connected to the supply of solvent. However, this shaking can inadvertently separate the vial from the supply of solvent and can lead to a loss or contamination of the drug or drug solution. Furthermore, shaking an assembly with a pointed implement is an unsafe practice.